Device for the deformation of sheet metal plates by means of shock waves



June 24, 1969 P. NEMITZ 3,451,238

DEVICE FOR THE DEFORMATION OF SHEET METAL PLATES BY MEANS OF SHOCK WAVESFiled Oct. 13, 1967 [/VVf/VTOR: PAUL NE/WTZ United States Patent 01:"fice 3,451,238 DEVICE FOR THE DEFORMATION F SHEET METAL PLATES BYMEANS OF SHOCK WAVES r Paul Nemitz, Kiel-Fries, Germany, assignor toAtlas-Mak Maschineubau 'GmbH., Kiel-Friedrichsort, Germany, a

' Filed Oct. 13, 1967, Ser. No. 675,098 Claims priority, applicatignGe7rmany, Nov. 15, 1966,

Int. Cl. B21a 26/08 US. Cl. 72-56 r 10 Claims ABSTRACT OI? THEDISCLOSURE 1 Background of the invention This invention relates to adevice for the deformation of sheet metal plates by means of explosiveforces and using a granular material insulation, in a water bath or by avacuum, during which deformation a holding down ring provides for thepressing of the edges of a sheet metal disk against the mold body edge.

Such devices are already known in the art. In one known embodiment, theholding down ring is secured by means of marginal screws to hold thesheet metal disk down but securing the sheet metal disks by means ofholding down rings in connection with marginal screws does not sufficefor large sheet metal disks. Already when deforming'hemispheres of onemeter in diameter there form folds at the outlet of the clamping ring inthe last phase ofthe deforming process owing to a raising of the holdingdown ring. These folds bring additional tension to bear on the marginalscrews already under maximum tension which makes unscrewing them muchmore dilficult.

Attempts have been made to overcome this deficiency by using hydraulicclamps in the form of screw clamps. However, this practice is notrealizable since the number of hydraulic clamps around the edge of themold must be so large and the weight of the clamps so high, that theope-ration is too expensive. Moreover, the connecting hoses for thehydraulic clamps hinder considerably operating the device.

Summary of the invention In order to avoid these disadvantages in thedeforming of large sheet metal disks, and to be able also to deformhighly rigid materials, the present invention provides a device for thedeformation of sheet metal plates by means of shock waves, whichcomprises a mold body having a mold impression formed therein; firstsupporting means associated with the mold body; a holding down ring forholding a sheet metal disk in position on said mold body; a plurality ofspaced apart second supporting means provided on the inner edge of theholding down ring; a plurality of clamping latches each positionedbetween said first supporting means associated with the mold body andsaid second supporting means on the holding down ring, and a vacuumconduit leading 3,451,238 Patented June 24, 1969 through the mold bodyand opening into the mold impression. I v

The first supporting means on the mold body may consist of an insideflange, or of a pivot which, in the case of need, is mounted on a pinwhich is removably inserted in the mold body. The second supportingmeans are advantageously adjustable.

The clamping latches may be provided with a bafile plate for bringingabout, by the striking shock effect, a strengthening of the clampingeffect of the holding down ring through the motion of the ends of theclamping latches towards the first and second supporting means. Withadjustable supporting means, the initial clamping stress of the sheetmetal disk is in many cases, particularly. with highly rigid sheet metaldisks, not suflicient. In the deivce proposed by the invention thestress is increased by means of shock waves.

Brief description of the drawing Several embodiments of the inventionwill now be described by way of example and with reference to theaccompanying drawing, in which:

FIG. 1 is a cross sectional view of a deforming device according to theinvention with inserted screw-adjustable clamping latches only one ofwhich is shown;

FIG. 2 is a similar view showing a modification of the adjustableclamping latch of FIG. 1;

FIG. 3 is a similar view showing a modification of the mold body andanother modification of the clamping latch of FIG. 1, wherein theclamping latch is pivotably connected to a pin removably inserted in thehousing of the mold body;

FIG. 4 is a similar view of further modifications of FIG. 1, showing amold body consisting of concrete and a clamping latch mounted on themold body hous- FIG. 5 is a similar view of a modification of FIG. 1showing a clamping latch consisting of two articulated levers, and

FIG. 6 is a side elevational view showing a still further modificationof the clamping latch of FIG. 1 that is adjustable in the socket of abafile plate by means of a screw thread. 1

Description of the preferred embodiment Referring with moreparticularity to the drawing in which like numerals designate likeparts, the deforming device shown in FIG. 1 consists of a mold body 2 inwhich a mold impression 1 is formed. The mold body 2 is made of caststeel and supports a mold body housing 7 formed integral with the moldbody 2. The housing 7 is open at its top. A sheet metal disk 4 to bedeformed by means of a shock under granular material insulation, in awater bath or by a vacuum, is placed onto the mold body 2 so that itcovers the mold impression 1. A holding down ring 5 which must be fixedduring the deformation process is introduced into the mold body housing7 from above and rests on the upper border zones of the sheet metal disk4.

FIGS. 1, 2 and 5 show first supporting means in the form of an inwardlydirected flange 8 projecting from the upper edge portion 6 of the moldbody housing 7. The holding down ring 5 shown in FIG. 1 has plurality ofspaced apart second supporting means in the form of upright supportingprojections 11 on its inside edge. A plurality of radially extendingclamping latches 9 carry each a baifie plate 10 and are positionedbetween the flange 8 and the upright supporting projections 11. Thesesupporting projections 11 and the clamping latches 9 are distributedaround the circumference of the mold body housing 7. The clampinglatches 9 are adjusted to the 3 thickness of the sheet metal plate 4 tobe clamped, and secured in their positions by means of screws 12(FIG. 1) or keys 13 ('FIG. 2). According to FIG. 6 the clamping latches9a are screwable in and out of a socket 3 on the baffle plate 10 therebymaking a tight clamping possible.

According to FIG. 5,the clamping latches are composed of two articulatedlevers 14 and 15 which support a baffle plate 10a. The uprightsupporting projection 11a is adjustable on the holding down ring bymeans of screws 16. The initial position of the articulated levers 14and 15 on the holding down ring 5 can be adjusted by the screws 16through the intermediary of the upright supporting projection 11a. Dueto the shock waves striking the bafile plates the articulated levers 14and will exert a high contact pressure in the direction of theirlengthening on the clamped sheet metal disk 4.

According to FIG. 3, a clamping latch 9b is mounted on a pivot 18 of apin 20 which is removably inserted in a mold body 2'.

FIG. 4 shows a mold body housing 7a in which a mold body 21 of concreteis accommodated and which supports the pivot '18 for a clamping latch90. The holding down ring 110 has, like the holding down ring 11b ofFIG. 3, an inclined outer surface 22 for engaging the clamping latches9b (FIG. 3) and 90 (FIG. 4), respectively.

*In order to bring about the shock effect, an explosive charge 17 islocated in the known manner above the sheet metal disk 4. The mold bodyhas a vacuum conduit 19.

It is to be noted that instead of cast steel and concrete also ice maybe used for the mold body.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. A device for the deformation of sheet metal plates by means of shock'waves, comprising (a) a mold body having a mold impression formedtherein;

(b) first supporting means associated with the mold body;

(c) a holding down ring for holding a sheet metal disk in'position onsaid mold body;

(d) a plurality of spaced. apart second supporting means provided on theinner edge of the holding down ring;

(e) a plurality of clamping latches '8 each positioned between saidfirst supporting means associated with the mold body and said secondsupporting means on the hold down ring, and

(f) a vacuum conduit leading through the mold body and opening into themold impression.

2. A deivce as claimed in claim 1, wherein a housing is supported by andformed integral with the mold body, said mold housing being open at itstop forthe introduction of the sheet metal disk to be deformed andhaving an inwardly directed flange at its upper edge portion whichconstitutes the first supporting means.

3. A device as claimed in claim 2, wherein a pivot on the mold bodyhousing about which the clamping latch can swivel radiallyforms thefirst support ing means.

4. A device as claimed in claim 3, wherein the pivot is mounted on a pinremovably inserted in an opening provided at the upper edge of the moldbody.

5. A device as claimed in claim 1, where the second supporting means arevariably adjustable by means of screws.

6. A device as claimed in claim 1, wherein the second supporting meansare variable by means of keys.

7. A device as claimed in claim '1, wherein the second supporting meansare adjustable on the holding down ring.

8. A device as claimed in claim 1, wherein the clamping latches are twoarticulated levers arranged to be lengthened by the shock waves.

9. A device as claimed in claim 1, whereing the clamping latches arevariable in length.

'10. A device as claimed in claim 1, wherein the clamping latches areprovided with baffie plates.

References Cited UNITED STATES PATENTS 3,068,822 12/1962 Orr et al.72-56 3,177,689 4/ 1965 Christian et al. 72-56 3,188,844 6/1965Schwinghamer 7256 RICHARD J. HERBST, Primary Examiner.

